My First Project Ever- 84 Regal Limited w/ Pontiac 400

[MrSony]

There are only really two types of pontiac V8s, small journal, and large journal. The Large Journal engines are the 421, 428, and the 455. Everything else (287, 317, 347, 370, 389, 195 4cyl, 326, 400, 350, the experimental 303, the 301, and the 265 [last pontiac put in a g body iirc]) are the small journal engines. Do you know anything about the guts? Cam? Compression? If you ever want a decent carb, get a quadrajet. BUT, be warned. The dual pattern aluminum edelbrock pontiac intakes (or at least all that I've seen) need to be clearances for a quadrajet to work as the freakin rear of the intake prevents the rear throttle blades from opening. In the meantime, or at least once it gets road worth, just keep pumping 93 in it. Last thing you want is for it to detonate itself to death. And NEVER. EVER. Put slicks or any sticky tire on that rear end. Traction and power is the enemy of the 7.5. Quick way to tell if it's a Th200r4 or a Th350 or whatever, Th200r4 has 4 forward gears. 1, 2, D/3, and OD/4. All others that came factory in g bodies (I think the 4 door cars like caprices and Delta 88s got the 700r4 iirc) were 3 speeds.

 

[CoelacanthsKill]

There are only really two types of pontiac V8s, small journal, and large journal. The Large Journal engines are the 421, 428, and the 455. Everything else (287, 317, 347, 370, 389, 195 4cyl, 326, 400, 350, the experimental 303, the 301, and the 265 [last pontiac put in a g body iirc]) are the small journal engines. Do you know anything about the guts? Cam? Compression? If you ever want a decent carb, get a quadrajet. BUT, be warned. The dual pattern aluminum edelbrock pontiac intakes (or at least all that I've seen) need to be clearances for a quadrajet to work as the freakin rear of the intake prevents the rear throttle blades from opening. In the meantime, or at least once it gets road worth, just keep pumping 93 in it. Last thing you want is for it to detonate itself to death. And NEVER. EVER. Put slicks or any sticky tire on that rear end. Traction and power is the enemy of the 7.5. Quick way to tell if it's a Th200r4 or a Th350 or whatever, Th200r4 has 4 forward gears. 1, 2, D/3, and OD/4. All others that came factory in g bodies (I think the 4 door cars like caprices and Delta 88s got the 700r4 iirc) were 3 speeds.

It has a mild cam, wish I knew compression. I have a invoice from a machine shop when the previous crank had broken and the engine was rebuilt.

 

[MrSony]

It has a mild cam, wish I knew compression. I have a invoice from a machine shop when the previous crank had broken and the engine was rebuilt.

View attachment 71314

Found your pistons. https://www.summitracing.com/parts/uem-1526-030/overview/make/pontiac

 

[MrSony]

Welp, I've come to this conclusion: Bit iffy on the specs on pontiacs, but if everything checks out your compression is 8:1.

 

[olds307 and 403]

I found the same thing. You can run 87 octane without any problem. Since the motor is mild, a quality rebuild on the 2004R with a hardened pump rings, stator, subshell and the big trans go kit should live fine behind that 400.

 

[Bonnewagon]

Welcome. And a big YOWSUH on that Pontiac motor! It looks like a pretty stock rebuild with good stuff. No valve job?!? The heads determine the compression ratio on a Pontiac and your '75/'76 version 6x's should be as stated above- 8 to 8.5 to 1. You can burn what ever's cheapest. Please try and find out what cam was used. If the car was set up for "racing" or something then the cam may be excessive and you can tell that by the crappy idle. A "mild" cam will idle smoothly. As for a transmission, I would try and find a common everyday Turbo 350 either used or rebuilt. It is strong, simple, cheap, and will slip right in place without you pulling your hair out.

 

[MrSony]

Get a good vacuum gauge and tune it for the most vacuum with timing and carb settings. You might have to chase around a bit between timing and air fuel mixture, but it'll make it run it's best. It'll also give you an idea how "aggressive" of a cam you have by the reading. Get it to idle as low as possible in park and tune idle screws for max vacuum and get a timing light. Just as a precaution, when you get to driving it, don't fill it with 87, put a gallon or three in there and see how the engine likes it. If it knocks or pings, adjust the timing. If it still does, your motor may have mods that you don't know about, but judging from the parts list on the sheet the shop gave, i'd say not.

 

[Bonnewagon]

I will say one thing that bothers me. I have never, ever, heard of a traditional Pontiac crankshaft breaking. My buddy was a crank grinder and he never saw that either. Ford and Chevy small blocks- always. Pontiac- never. So I wonder what the prior owner was up to?!? I'm also puzzled by the fuel cell, headers, and all the other "race car" nonsense. You may have someones bastardized project to deal with. You can get a normal gas tank easy enough, and recover your cruising range. But I hope that there is a streetable rear end with gears you can actually use. Also verify the transmission. If it indeed is a T-400 as advertised then by all means get it fixed. They are getting hard to find and require a different cross-member, driveshaft, and yokes to run in our cars. But if it is a weak T-200 then I again say the T-350 is best for you.

 

[Dinosport]

I Like it, welcome to the forum. I haven't seen those centerlines in a long time especially clean like those. I have a gas tank I would give you if you were closer. Pontiac 400's i haven't seen one of those either in along time. I think you have a good starting point. My first suggestion is how does the motor start, idle, rev up. If it seems fine don't touch anything for now. Go one step at a time or you can end up with headaches. Deal with the trans issue. Figure out what it is. If its worth fixing cool if not find one. If money is tight then best solution if its available to you is to find a used one from someone you trust. Once its running put a few miles on it, then you should be able to determine what you should tackle next.
As for the rust, Im no body guy by any means but I might suggest sanding the rusty areas and re primer there so it doesn't spread. Beware though that the rust you see is usually like triple the size under the paint.

 

[CoelacanthsKill]

I Like it, welcome to the forum. I haven't seen those centerlines in a long time especially clean like those. I have a gas tank I would give you if you were closer. Pontiac 400's i haven't seen one of those either in along time. I think you have a good starting point. My first suggestion is how does the motor start, idle, rev up. If it seems fine don't touch anything for now. Go one step at a time or you can end up with headaches. Deal with the trans issue. Figure out what it is. If its worth fixing cool if not find one. If money is tight then best solution if its available to you is to find a used one from someone you trust. Once its running put a few miles on it, then you should be able to determine what you should tackle next.
As for the rust, Im no body guy by any means but I might suggest sanding the rusty areas and re primer there so it doesn't spread. Beware though that the rust you see is usually like triple the size under the paint.

Centerlines are just some cheap ones that just so happen to polish up nicely. Motor starts right up. Idles a little fast but I haven't adjusted carb at all and haven't adjusted timing either. Waiting for new throttle return springs + bracket and exhaust flange gaskets before I move it again. If it is a weak 200, I have a 350 that came with the purchase, but the kid told me it needs a complete rebuild. Rust will be tackled soon